SU739397A1 - Device for ultrasonic flaw detection of products - Google Patents

Description

(54) DEVICE FOR ULTRASONIC CONTROL OF PRODUCTS

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The invention relates to non-destructive ultrasonic testing and can be used to control the integrity of coarse-grained media.

Known. an ultrasonic flaw detector containing an oscillator, a transducer, a signal extraction circuit to a width control circuit 1.

The disadvantage of it is the low mechanical complexity.

Nia closer to the invention in its technical essence and the achieved result is a device for ultrasonic testing of products containing a series-connected synchronizer, a generator of frequency-modulated oscillations, an amplifier, a filter and a recorder, a broadband transducer connected to the output of the generator 2.

A disadvantage of the known device is its low noise immunity.

-The purpose of the invention is to increase the noise immunity of the device.

The goal is achieved by the fact that the device is equipped with a gating pulse generator connected in series between a detector, an adder and a threshold stage, a gating pulse generator whose input is connected to the synchronizer output, the first output to the second amplifier input, and the second output to the second input of the threshold cascade , a prism, on the surface of which a broadband transducer is installed, having an axis with a roller, interacting kinematically with a surfactant and electrically - synchronizes with the input pa.

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The drawing shows the functional diagram of the device.

 The device contains a synchronizer 1 connected in series, a generator 2 of frequency-modulated oscillations, an amplitude 5 tel 3, file 4, a detector 5, an adder 6, a threshold stage 7 and a recorder 8. In addition, the device contains a 9 strobe generator, the input of which is connected to the output synchronizer, the first output - to the second input of the amplifier, and the second output - to the second input of the threshold

20 cascade. On the surface of the prism 10 is installed a broadband transducer 11. The transducer 11 has an axis with a roller 12 on which a magnet 13 is fixed. Magnet

, (: in the reed with reed switch 14, through which the power supply 15 is connected to the synchronizer 1.

The device works as follows

By rotating the roller 12 to one side or the other, the broadband converter 11 moves along the surface of the prism 10. The magnet 13 closes the normally open contacts of the reed switch 14, through which the voltage from the power source 15 is fed to the synchronizer 1. The signal from the synchronizer 1 is fed to the generator 9 gate. pulses, which generates a pulse, damping in the amplifier 3 probe and given pulses. At the same time, the synchronizer 1 generates a frequency-modulated pulse in the generator 2. Passing a prism 10, the thickness of which is selected from the condition that the ultrasonic pulse travels from the insertion point into the prism 10 to the defect when transducer II is moved, the energy of the probe pulse is spent on reflection from the structure and discontinuity (defect) and after being converted into electrical impulses is distributed within the cycle and enters the input of the amplifier 3, the bandwidth of which is consistent with the width of the spectrum of the probe pulse. The pulses amplified in the amplifier 3 pass through a filter 4, at the output of which pulses are formed corresponding to the signals from the defect and the structure. At a certain ratio of the defect area and the grain size of the structure, as well as depending on their orientation, the signal spectrum from the defect contains all of its frequency components, and the signal spectra from the structure grains change when the direction of propagation of the probe pulses changes. This contributes to the optimal compression of the impulses from the defect and not optimal from the grains of the structure; therefore, the amplitudes of the compressed pulses corresponding to the signals from the defect have a large amplitude compared to the amplitudes of the impulses corresponding to the signals.

from the grains of the structure, while their temporal positioning when moving the converter 11 is different. Next, the pulses are detected in detector 5 and summed by applying clock ticks in adder 6. At the same time, the amplitude of the pulses corresponding to signals from the defect from tact to clock increases due to the summation of the amplitudes of the signals of each cycle, and the amplitudes of the pulses corresponding to signals from the structure grains add and their growth is insignificant.

The pulses are then passed through the threshold cascade 7 and are recorded in the recorder 8. The use of the invention improves the noise immunity of the inspection of articles made of large-structured materials.

Claims (2)

1. USSR author's certificate number 279146, cl. G 01 N 29/04, 1969.. 2. USSR author's certificate No. 284394, cl. G 01 N 29/00, 1970 (prototype).